Hydrothermal synthesis of MoS2-decorated silicon nanowires heterostructure with enhanced performance of photocatalytic activity under visible light

Abstract

Molybdenum disulfide (MoS2) is weakly stacked by vander Waals force, and the interaction force between the layers of MoS2 and Silicon is weak. Therefore, direct growth of homogeneous high quality MoS2 films on silicon substrates stays challenging. Herein, for the first time, few layered MoS2nanosheetswere successfully deposited onto silicon nanowires (SiNWs) through hydrothermal process. First, as prepared MoS2/SiNWs heterostructure was characterized by using Raman spectroscopy, Scanning Electron Microscopy (SEM) and by means of the Energy-Dispersive X-ray spectroscopy (EDX). Second, the photocatalytic activity ofsynthesizedMoS2/SiNWs photocatalyst was systematically evaluated for the decoloration of methylene blue (MB) under visible light irradiation. It was found that MoS2/SiNWs heterostructure exhibited excellent photocatalytic activity against this dye compared with synthesized SiNWs films. Also, it was found that after irradiation during 180 min, the MoS2/SiNWs film exhibited the highest photocatalytic efficiency (90%), in comparison to SiNWs (62%). Finally, it is assumed that the photocatalytic activity improvement was attributed to visible light absorption improvement, the enhancement of the photogenerated electron-hole pair’s separation efficiency. Moreover, thanks to the nanoflowers structure assembled by nanosheets with few layers, the specific surface area was increased offering more sites for MB pollutant adsorption.